The world's longest sea-crossing bridge is set to open to the public Wednesday, marking the completion of a $20 billion project that took nine years to construct, CNN reported.

The 36-mile structure, which will connect Hong Kong and Macau to the mainland Chinese city of Zhuhai, was initially meant to open in 2016 but that date has been pushed back by numerous delays.

The opening ceremony will be held in Zhuhai on Tuesday and is expected to be attended by Chinese President Xi Jinping as well as top officials from Hong Kong and Macau.

At a press briefing Monday, secretary for Transport and Housing, Frank Chan Fan, said the bridge was a joint collaboration between Guangdong, Hong Kong and Macao, and would significantly reduce traveling times between the regions.

He added that the project would also strengthen trade, finance, logistics and tourism between the three regions and see Hong Kong assume a "more proactive role in the development of the Greater Bay Area."

By 2025, experts expect the region's economy to nearly double that number.

"The government wants to use the Greater Bay Area to close the [technological] gap on the U.S., Japan and other developed nations," said Edmond Wu, an economics professor at the South China University of Technology in Guangzhou. "There is a culture of innovation because Guangdong province and Shenzhen have always been the cradle of reform in China."

This week Chan noted the bridge would be "instrumental in enhancing the flow of people, goods and capital, as well as technological collaboration within the region."

He added that the focus now is to "make the best use of the topside development at the artificial island and to capitalize on the strategic advantage of the bridge."